KR20160007786A - Display device - Google Patents

Abstract

The present invention relates to a display device, and more particularly to a display device that converts input image data into compensated image data using a compensation value when input image data corresponding to a horizontal line for sensing for external compensation is received, And to output the compensated data voltage corresponding to the compensated image data to the data line before and after the compensated image data is made. To this end, a display device according to the present invention includes: a panel having subpixels formed therein so that sensing for external compensation can be performed for each horizontal line; A sensing unit for performing sensing for external compensation for each horizontal line of the panel to collect sensing data; A calculating unit for determining a characteristic change of each subpixel using the sensing data and calculating an external compensation value; A data arrangement unit for converting the input image data into compensated image data using a compensation value when the input image data corresponding to the horizontal line on which the sensing is performed is received; And outputting a compensated data voltage corresponding to the compensated image data to the data line formed on the panel before and after the sensing, and when the sensing is performed, And a data driver for outputting the data.

Description

Display device {DISPLAY DEVICE}

The present invention relates to a display device, and more particularly, to a display device capable of performing external compensation through a sensing line.

Flat panel display devices (FPDs) are used in various types of electronic products including mobile phones, tablet PCs, and notebook computers. The flat panel display device includes a liquid crystal display device (LCD), a plasma display panel device (PDP), and an organic light-emitting diode display device (OLED) Electrophoretic display devices (EPDs) are also widely used.

In particular, the organic light emitting diode (OLED) uses a self-luminous element that emits light by itself, and thus has advantages such as a fast response speed, a high luminous efficiency, a high luminance, and a large viewing angle.

That is, the organic light emitting display device is a self light emitting device that emits an organic light emitting diode by using an electron and a hole recombination to display an image, has a high response speed and low power consumption, and uses a self light emitting device Therefore, it has an excellent viewing angle. Therefore, the organic light emitting display device is attracting attention as a next generation flat panel display.

However, in the conventional organic light emitting display device, a characteristic deviation such as a threshold voltage (Vth) and mobility of the driving transistor occurs for each pixel for reasons of process variation, deterioration and the like. Therefore, the amount of current for driving each of the organic light emitting diodes is different, thereby causing a luminance deviation between the pixels.

In order to solve the above problem, Korean Patent Laid-Open Publication No. 10-2013-0066449 (hereinafter referred to as "Prior Art Document") discloses a technique for compensating for a change in characteristics of driving transistors included in each pixel through correction of input image data An external compensation method is disclosed.

1 is a diagram illustrating an example of a horizontal line in which sensing for external compensation is performed in a conventional OLED display. In FIG. 1, point A represents any one subpixel formed on a horizontal line where no sensing is performed for external compensation, and point B represents a subpixel formed on a horizontal line where external sensing is performed. Lt; / RTI > 1 (a) shows the luminance at the point A, and FIG. 1 (b) shows the luminance at the point B. FIG.

In an organic light emitting display, the sensing for external compensation is generally performed in units of one horizontal line, in particular, at a vertical blank time between a frame and a frame.

In this case, in the horizontal line where sensing for external compensation is performed, no image is output at the vertical blank time. Accordingly, the horizontal line where the sensing for external compensation is performed is indicated by a dark line as shown in Fig. For example, since the image is not output in the subpixels formed on the horizontal line where sensing for external compensation is performed, the horizontal line has a low luminance as compared with other horizontal lines.

More specifically, as shown in FIG. 1 (b), in a subpixel in which sensing for external compensation is performed, a period (No emission) in which the subpixel does not emit light is generated. In this case, the micro-emission period (No emission) in which the organic light emitting diode does not emit light includes not only a period during which the sensing is performed, but also a period during which the organic light emitting diode emits light The charging period (curve section) is also included.

However, as shown in Fig. 1 (a), a sub-pixel for which no sensing is performed for external compensation, continuously emits light.

Therefore, the luminance of the horizontal line for sensing for external compensation is lower than the luminance of the horizontal line for which no external compensation is performed. Accordingly, the horizontal line where the sensing for the external compensation is performed is displayed to the user's eyes.

The phenomenon in which the horizontal line is visible to the user's eyes is seriously generated in the pixels which are emitted in low gray. For example, since the current level is lower in a pixel which emits light in low gray, the anode short-circuit charging period becomes longer. Therefore, the non-light emitting area becomes long, and thus, the phenomenon that the horizontal line is visible to the user's eyes is intensified.

In addition, the degree of the visual phenomenon in which the horizontal line is visible to the user's eyes may be different at the top and bottom of the panel.

The above-described phenomenon can be generally generated in an organic light emitting display. However, the above-described phenomenon may occur in various kinds of display devices using external compensation in addition to the organic light emitting display device.

The present invention has been proposed in order to solve the above-described problems. When input image data corresponding to a horizontal line for sensing for external compensation is received, the input image data is converted into compensated image data using a compensation value And to output a compensated data voltage corresponding to the compensated image data to the data line before and after the sensing is performed.

According to an aspect of the present invention, there is provided a display device including: a panel having subpixels formed therein, the sensing being performed for each horizontal line; A sensing unit for performing sensing for external compensation for each horizontal line of the panel to collect sensing data; A calculating unit for determining a characteristic change of each subpixel using the sensing data and calculating an external compensation value; A data arrangement unit for converting the input image data into compensated image data using a compensation value when the input image data corresponding to the horizontal line on which the sensing is performed is received; And outputting a compensated data voltage corresponding to the compensated image data to the data line formed on the panel before and after the sensing, and when the sensing is performed, And a data driver for outputting the data.

According to the present invention, the level of the horizontal line on which the sensing for real-time external compensation is performed can be reduced. Thus, the inconvenience of the user can be reduced.

1 is a diagram illustrating a horizontal line in which sensing for external compensation is performed in a conventional organic light emitting diode display.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting diode (OLED) display.
4 is a view illustrating a configuration of a data driver applied to an OLED display according to an embodiment of the present invention.
5 is a view illustrating a structure of pixels formed on a panel applied to an OLED display according to an exemplary embodiment of the present invention.
6 is a view illustrating a structure of a pixel formed on a panel applied to an OLED display according to an embodiment of the present invention.
7 is a flow chart of an embodiment of a method of driving an organic light emitting display according to the present invention.
8 is a view illustrating a state in which a data voltage is output to each horizontal line of the OLED display according to the present invention.
FIG. 9 is a graph illustrating brightness of a horizontal line where sensing is performed and a horizontal line where sensing is not performed in the organic light emitting display according to an embodiment of the present invention.
10 is a graph illustrating a magnitude of a compensation value applied to an OLED display according to an exemplary embodiment of the present invention.
11 is a graph illustrating a magnitude of a compensation value applied to an OLED display according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention can be applied to various kinds of display devices using external compensation. Hereinafter, for convenience of explanation, an organic light emitting display device will be described as an example of the present invention.

FIG. 2 is a schematic view illustrating the structure of an organic light emitting display according to the present invention, FIG. 3 is a view illustrating a structure of a control unit applied to the organic light emitting display according to the present invention, and FIG. FIG. 5 is a view illustrating a structure of pixels formed on a panel applied to the organic light emitting diode display according to the present invention, and FIG. 6 is a cross- FIG. 5 is a view illustrating a structure of a pixel formed on a panel applied to an organic light emitting display according to an embodiment of the present invention.

The present invention is intended to reduce the phenomenon in which the line where the sensing is performed is visible to the user's eyes when external compensation is performed in real time.

In general, when the sensing for real-time external compensation is performed using the blank time, during the frame period after the threshold voltage Vth or mobility of each pixel is sensed, The same data voltage as the original data voltage is output through the data line. However, during the period of sensing for external compensation, since the pixel can not emit light, the horizontal line at which sensing is performed can be seen darker to the user's eyes.

The present invention is intended to prevent a phenomenon in which the luminance of the horizontal line on which the sensing is performed falls, and a line that is not sensed is seen on the user's eyes. To this end, according to the present invention, during a normal writing period before a sensing operation and during a recovery writing period after a sensing operation, a compensated data voltage having an additional data voltage added to the original data voltage Is supplied to the data line, it is possible to prevent the luminance of the line on which the sensing is performed from being lowered. Accordingly, the phenomenon that the horizontal line on which the sensing is performed is visible to the user's eyes can be reduced. The additional data voltage corresponds to the compensation value described below.

As shown in FIGS. 2 to 6, the organic light emitting display according to the present invention includes subpixels P formed of organic light emitting diodes (OLED), and sensing for external compensation is performed for each horizontal line A sensing unit 320 that performs sensing for external compensation for each horizontal line of the panel 100 and collects sensing data, and a sensing unit 320 for sensing characteristics of each subpixel A calculation unit 410 for determining a change and calculating an external compensation value, and a correction unit 420 for converting the input image data to compensated image data using the compensation value when the input image data corresponding to the horizontal line on which the sensing is performed is received A data alignment unit 430 and a compensated data voltage corresponding to the compensated image data before and after the sensing are formed on the panel And outputs to the data lines, a data driver 300 to be output when the sensing data of the sensing voltage to the data line. Here, the sensing unit 320, the calculating unit 410, the data arranging unit 430, the data driver 300, and the gate driver 200 are collectively referred to as a panel driving unit.

6, the panel 100 includes a pixel driving circuit (not shown) including an organic light emitting diode OLED and a driving transistor Tdr for controlling a current flowing through the organic light emitting diode OLED (PDC), and a signal line for defining a pixel region where the subpixels 110 are formed and supplying a driving signal to the pixel driving circuit PDC.

First, the signal lines are connected to a scan control line SCL, a sensing control line SSCL, a data line DL, a sensing line SL, a first driving power supply line PLA and a second driving power supply line PLB Includes.

Next, the scan control lines SCL are formed so as to be spaced apart from each other along the second direction of the panel 100, that is, the horizontal direction.

Next, the sensing control lines SSCL may be formed at regular intervals to be parallel to the scan control lines SCL. In addition, the scan control line and the sensing control line may be formed as a single line.

Next, the data lines DL are arranged to have a predetermined interval along the first direction, i.e., the longitudinal direction, of the panel 100 so as to cross the scan control line SCL and the sensing control line SSCL, .

Next, the sensing lines SL may be formed at regular intervals to be parallel to the data lines DL.

At least three of the sub-pixels 110 form one unit pixel 120. In the following description, four sub pixels 110 (red pixel (R), white pixel (W), green pixel (G) and blue pixel (B) The present invention will be described by way of example in the case where the pixel 120 is formed. In this case, one sensing line is formed in the unit pixel 120. Therefore, when d data lines DL1 to DLd are formed on the horizontal line of the panel 100, the number k of the sensing lines SL is d / 4.

In other words, the data lines are formed in the first direction (vertical direction) of the panel 100, the sensing lines SL are formed in parallel with the data lines, SL are connected to at least three sub-pixels 110 constituting each unit pixel 120 formed in one horizontal line, as shown in FIG.

Next, the first driving power supply line PLA may be formed at regular intervals to be parallel to the data lines DL. Here, the first driving power line PLA may be spaced apart from the sensing line SL at regular intervals. The first driving power supply line PLA is connected to a driving power supply unit (not shown) and supplies a first driving power supply EVDD supplied from a driving power supply unit (not shown) to each pixel P.

The second driving power line PLB is formed on the entire surface of the panel 100 or connected to the data lines DL1 to DLd or the scan control lines SL1 to SLk, Or may be formed at regular intervals to be parallel to each other. The second driving power supply line supplies a second driving power (EVSS) supplied from a driving power supply unit to each pixel P. Alternatively, the second driving power supply line may be electrically grounded to a case (or a cover) of a metal material constituting the organic light emitting display. In this case, (Ground).

Finally, each of the plurality of pixels P is formed for each pixel region defined by each of the scan control lines (SCL) and the data lines DL1 to DLd, which intersect with each other. Here, each of the plurality of pixels P may be any one of a red pixel, a green pixel, a blue pixel, and a white pixel.

One unit pixel 120 includes adjacent red subpixels, white subpixels, green subpixels, and blue subpixels, or may include red subpixels, green subpixels, and blue subpixels, as shown in FIG. 5 . 4 shows two unit pixels 120 each composed of a red subpixel R, a white subpixel W, a green subpixel G and a blue subpixel B. In FIG.

Each of the plurality of subpixels P may include a pixel driving circuit (PDC) and an organic light emitting diode (OLED) as shown in FIG.

The pixel driving circuit PDC includes a first switching transistor Tsw1, a second switching transistor Tsw2, a driving transistor Tdr, and a capacitor Cst. The transistors Tsw1, Tsw2, and Tdr may be a thin film transistor (TFT), such as an a-Si TFT, a poly-Si TFT, an oxide TFT, and an organic TFT.

The first switching transistor Tsw1 is switched by the first scan pulse SP1 and outputs a data voltage Vdata supplied to the data line DL. The first switching transistor Tsw1 includes a gate electrode connected to an adjacent scan control line SCL, a first electrode connected to an adjacent data line DL and a first electrode connected to a gate electrode of the driving transistor Tdr lt; RTI ID = 0.0 > d1. < / RTI >

The second switching transistor Tsw2 is switched by the second scan pulse SP2 to apply the reference voltage Vref supplied to the sensing line SL to the second node n2 which is the source electrode of the driving transistor Tdr Supply. To this end, the second switching transistor Tsw2 includes a gate electrode connected to an adjacent sensing control line SSCL, a first electrode connected to an adjacent sensing line SL and a second electrode connected to a second node n1 .

The capacitor Cst includes electrodes connected between the gate electrode of the driving transistor Tdr and the first electrode, that is, the first and second nodes n1 and n2. A first electrode of the capacitor Cst is connected to the first node n1 and a second electrode of the capacitor Cst is connected to the second node n2. The capacitor Cst charges the difference voltage of the voltage supplied to the first and second nodes n1 and n2 according to the switching of the first and second switching transistors Tsw1 and Tsw2, And switches the driving transistor Tdr according to the voltage.

The driving transistor Tdr controls the amount of current flowing from the first driving power supply line PLA to the organic light emitting diode OLED by being turned on by the voltage of the capacitor Cst. The driving transistor Tdr includes a gate electrode coupled to the first node n1, a first electrode coupled to the second node n2, and a second electrode coupled to the first driving power line PLA. do.

The organic light emitting diode OLED emits light having a luminance corresponding to the data current Ioled by the data current Ioled supplied from the driving transistor Tdr. For this, the organic light emitting diode OLED includes a first electrode (for example, an anode electrode) connected to the second node n2, that is, a first electrode of the driving transistor Tdr, An organic layer (not shown) and a second electrode (e.g., a cathode electrode) connected to the organic layer. The second electrode of the organic light emitting diode may be the second driving power supply line PLB formed on the organic layer or may be additionally formed on the organic layer to be connected to the second driving power supply line PLB.

In the above description, the structure of the subpixel 110 for performing external compensation has been described with reference to FIG. 6. However, the subpixel 110 may be formed in various structures in addition to the structure shown in FIG. 6 .

For example, the external compensation is a method of calculating the amount of change in threshold voltage or mobility of the driving transistor Tdr formed in the subpixel 110, and calculating the amount of change of the data voltage supplied to the unit pixel It means to vary the size. Therefore, the structure of the sub-pixel 110 can be changed into various forms so that the threshold voltage or the variation amount of the mobility of the driving transistor Tdr can be calculated.

The method of calculating the amount of change in threshold voltage or mobility of the driving transistor Tdr using the subpixel 110 for external compensation is also variously changed according to the structure of the subpixel 110 .

In addition, the present invention relates to a method for preventing noise lines generated during external compensation in an organic light emitting display device performing external compensation, The structure of various subpixels proposed for external compensation and various external compensation methods. For example, the structure of the subpixel for external compensation and the method of performing external compensation can be applied to structures and methods disclosed in a number of patents, including Japanese Laid-Open Patent Application No. 10-2013-0066449 And the invention disclosed in Application No. 10-2013-0150057 and Application No. 10-2013-0149213 filed by the present applicant may also be applied.

That is, the specific structure of the subpixel for performing external compensation and the specific method of external compensation are outside the scope of the present invention. Thus, an example of a subpixel for external compensation has been briefly described with reference to FIG. 6, and an external compensation method is also briefly described below.

Second, the panel driving unit operates the panel 100 in a sensing mode or in a display mode.

The sensing mode may be performed every cycle set by the user or at a blank time at which no image is displayed. In the sensing mode, an external compensation value for correcting the characteristic change of the driving transistor Tdr is calculated. In addition, in the sensing mode, when input image data corresponding to a horizontal line on which sensing is performed is received, the input image data is converted into compensated image data using a compensation value, and compensation data voltages Is supplied to the panel through the data line.

In the display mode, an image is output to the panel 100. In the display mode, the input image data is converted into external compensation image data using the external compensation value, and the external compensation data voltage corresponding to the external compensation image data is supplied to the panel through the data line.

The panel driving unit may control a characteristic change of the driving transistor Tdr included in each subpixel P through the first through kth sensing lines SL1 through SLk in the sensing mode, Threshold voltage and / or mobility) to generate sensing data (Sdata).

The panel driver calculates the external compensation value based on the sensing data Sdata and uses the external compensation value to calculate input image data Ri, Gi, Bi input from an external system (not shown) And generates external compensation video data. The panel driver converts the external compensation video data (DATA) into a data voltage and supplies the data voltage to the corresponding subpixel (P).

For example, the panel driver may drive each of the driving transistors Tdr through each of the sensing lines SL1 to SLk in order to individually compensate for a characteristic change of the driving transistors Tdr included in each subpixel P, And compensates the input image data Ri, Gi, Bi using the characteristic variation amount of each of the sensed driving transistors Tdr, and compensates the compensated external compensation image data to the external compensation data voltages And supplies them to the respective sub-pixels (P).

The panel driving unit includes a sensing unit 320 for performing sensing for external compensation for each horizontal line of the panel and collecting sensing data, a controller 320 for determining a characteristic change of each subpixel using the sensing data, A data alignment unit 430 for converting the input image data into compensated image data using the compensation value when the input image data corresponding to the horizontal line on which the sensing is performed is received, And outputs the compensated data voltage corresponding to the compensated image data to a data line formed in the panel 100 before sensing and after the sensed data is sensed, A data driver 300 for outputting the data to the scan lines and the scan control lines SCCL, And a gate driver 200 for supplying a first scan pulse SP1 and a second scan pulse SP2. The data arrangement unit 430 is formed in a control unit 400 that controls the data driver 300 and the gate driver 200. The calculating unit 410 may be included in the control unit 400 or may be formed independently of the control unit 400. The sensing unit 320 may be formed in the data driver 300 or independently of the data driver 300. The sensing unit 320 is included in the data driver 300 as shown in FIG. 4 and the calculating unit 410 may include the controller 400 An organic light emitting display according to the present invention will be described as an example. In this case, the data driver 300 may include a data voltage supplier 310 for supplying various data voltages to the panel and the sensing unit 320, as shown in FIG. That is, when the sensing unit 320 is included in the data driver 300, the data voltage supply unit 310 is the same as the data driver 300, And a voltage output unit 310. However, the panel driving unit, which is applied to the organic light emitting display according to the present invention, may have various structures other than the structures described below.

The control unit 400 controls the gate driver 200 and the gate driver 200 based on a timing control signal GCS for controlling the driving of the gate driver 200 based on a timing synchronization signal TSS input from an external system And a data control signal (DCS) for controlling the driving of the data driver 300. [

In addition, in the sensing mode in which sensing for external compensation is performed, the controller 400 transmits sensing image data to be supplied to the pixels formed on the horizontal line where external compensation is performed, to the data driver 300. The sensing for the external compensation can be performed at various timings, but the present invention will be described below as an example in which the external compensation is performed at a blanking time between a frame and a frame. The controller 400 calculates the external compensation value based on the sensing data Sdata provided from the data driver 300 in the sensing mode and stores the external compensation value in the memory 450. The memory 450 may be included in the controller 400 or may be independently formed outside the controller 400.

When the input image data corresponding to the horizontal line for sensing for external compensation is received in the display mode in which the image is output, the control unit 400 uses the compensation value to convert the input image data into the compensated image data . When the input image data corresponding to the horizontal line not to be sensed is received in the display mode, the control unit 400 controls the display unit 410 to display the input image data, Data is subjected to external compensation using the external compensation value to convert it into external compensation video data, or the input video data is rearranged without external compensation and converted into general video data and outputted.

3, the control unit 400 uses the timing synchronization signal transmitted from the external system (not shown) to input the input image data transmitted from the external system (GCS), the data control signal (DCS), and the data control signal (DCS) using the timing synchronization signal, a data alignment unit 430 for rearranging the data signals and supplying the rearranged output image data to the data driver 300, A control signal generating unit 420 for generating a power control signal PCS and a control unit 420 for controlling the characteristics of the driving transistor formed in each of the pixels using the sensing data Sdata transmitted from the data driver 300 A calculation unit 410 for calculating an external compensation value to compensate, and a compensation value calculation unit 410 for storing the compensation value prepared for the present invention And an output unit 440 for outputting various output image data and various control signals generated by the data arrangement unit 430 to the data driver 300 or the gate driver 200 do.

The calculating unit 410 determines the characteristic change of each subpixel using the sensing data, and calculates the external compensation value. For example, in the sensing mode, the calculating unit 410 senses a characteristic change of the organic light emitting diodes using the sensing data (Sdata), calculates the external compensation value according to the characteristic change The external compensation value may be stored in the memory 450. In this case, in the display mode, the data sorting unit 430 corrects the input image data using the external compensation value, and transmits the corrected external compensation image data to the data driver 300.

In the display mode, the data sorting unit 430 rearranges the input image data according to the structure of the subpixels 110, and then supplies the rearranged output image data to the data driver 300. In particular, the data arrangement unit 430 may correct the input image data using the external compensation value and the compensation value.

For example, in a sensing mode in which sensing for external compensation is performed, the data arranging unit 430 supplies sensing image data to be supplied to subpixels formed on a horizontal line where external compensation is performed, to the memory 450 And transmit the data to the data driver 300.

When the input image data corresponding to the horizontal line on which the sensing for external compensation is performed is received in the display mode in which the image is output, the data aligning unit 430 arranges the input image data using the compensation value Into the compensated image data. That is, when the input image data corresponding to the horizontal line on which the sensing is performed is received, the data sorting unit 430 adds the compensation value to the input image data, and converts the sum into the compensation image data.

In addition, in the display mode, when the input image data corresponding to the horizontal line in which the sensing is not performed is received, the data sorting unit 430, in accordance with the calculating unit control signal transmitted from the calculating unit 410, The input image data is subjected to external compensation using the external compensation value to convert it into external compensation image data, or the input image data is rearranged without external compensation, and converted into general image data and output.

That is, in the display mode, when input image data corresponding to the horizontal line on which the sensing is not performed is received, if the external compensation for the input image data is requested, And if the external compensation for the input image data is not required, the input image data is rearranged according to the structure of the panel and converted into the general image data.

Accordingly, the data arrangement unit 430 generates the sensing image data in the sensing mode, and generates the compensation image data, the external compensation image data, and the general image data in the display mode. The sensing image data, the compensation image data, the external compensation image data, and the general image data are generically referred to as output image data.

The control signal generator 420 generates various control signals required in the present invention.

The memory 450 stores the compensation value and the external compensation value transmitted from the calculation unit 410 and transmits the compensation value to the data arrangement unit 430 as described above.

The gate driver 200 sequentially generates a first scan pulse SP1 in response to a gate control signal GCS supplied from the controller 400 and sequentially supplies the first scan pulse SP1 to the scan control lines SCL, And sequentially generates a second scan pulse SP2 in response to the gate control signal GCS and sequentially supplies the second scan pulse SP2 to the sensing control lines SSCL. Here, the gate control signal GCS may include a start signal, a plurality of clock signals, and the like.

The gate driver 200 may be formed directly on the panel 100 together with the thin film transistor forming process of each subpixel P or may be formed in the form of an integrated circuit (IC) and mounted on the panel.

The data driver 300 is connected to the data lines DL1 to DLd and the sensing lines SL1 to SLd and operates in a sensing mode or a display mode according to a control signal transmitted from the controller 400 . 4, when the data driver 300 includes the data voltage output unit 310 and the sensing unit 320, the data voltage output unit 310 outputs the data voltage DL to the data line DL, And the sensing unit 320 is connected to the sensing lines SL.

The sensing unit 320 supplies a reference voltage Vref to each of the sensing lines SL1 to SLk in the sensing mode and receives a signal corresponding to the reference voltage, And senses the characteristic change of the driving transistor Tdr included in the subpixels P formed on the line to generate the sensing data Sdata.

The sensing unit 320 provides the generated sensing data Sdata to the controller 400. [

To this end, the subpixels are configured as shown in FIG. For example, one sensing line SL is provided for each unit pixel 120 including R, G, B, and W subpixels 110 among the subpixels formed on one horizontal line Respectively. Accordingly, when one sensing data voltage is supplied through each sensing line SL, the sensing data for one subpixel of each unit pixel 120 is transmitted to the sensing unit 320. [ Since one unit pixel 120 is formed of four subpixels, when four sensing data voltages are supplied through the sensing line SL, the number of subpixels Sensing data can be generated. The sensing data for all the subpixels formed on the one horizontal line is transmitted to the calculating unit 410. The calculating unit 410 calculates the external compensation for the subpixels using the sensing data, Value can be calculated.

In the sensing mode, the data voltage output unit 310 converts the output image data transmitted from the controller 400, that is, the sensing image data, into a sensing data voltage and supplies the sensed data voltage to the data line. In the display mode, the data voltage output unit 310 outputs the output image data (image data) supplied from the control unit 400 on a horizontal line basis using a plurality of reference gamma voltages supplied from a reference gamma voltage supply unit DATA) into data voltages and supplies them to the corresponding data lines DL1 to DLd. The output image data transmitted to the data voltage output unit 310 in the display mode is the external compensation image data or the compensation image data.

That is, the data voltage output unit 310 samples the output image data DATA of each subpixel P input in units of one horizontal line according to the data control signal DCS, The gamma voltage corresponding to the gray level value of the sampling data is selected as the data voltage and supplied to the data line DL of the corresponding sub pixel P.

The sensing unit 320 senses the voltage of each of the sensing lines SL1 to SLk in the sensing mode and generates sensing data Sdata corresponding to the sensing voltage to provide the sensed data to the controller 400 . For this, the sensing unit 320 may include an analog-to-digital converter for converting the sensing voltage transmitted from the sensing lines to digital to generate the sensing data (Sdata).

The sensing unit 320 performs sensing at a blank time that is formed between a frame and a frame and does not output a data voltage to the data lines.

FIG. 7 is a flowchart illustrating a method of driving an organic light emitting display according to an exemplary embodiment of the present invention. FIG. 8 is a view illustrating a state in which a data voltage is output to each horizontal line of the organic light emitting display according to the present invention. FIG. 9 is a graph showing an example of a horizontal line in which the sensing is performed and a horizontal line in which no sensing is performed in the organic light emitting display according to an embodiment of the present invention. FIG. 11 is a graph illustrating a magnitude of a compensation value applied to an OLED display according to another embodiment of the present invention. Referring to FIG. Particularly, FIG. 8 shows a state in which an image is outputted on each horizontal line. 9, point A represents any one subpixel formed on a horizontal line where no sensing is performed for external compensation, and point B represents a subpixel formed on a horizontal line where sensing is performed for external compensation ≪ / RTI > 9 (a) shows the luminance at the point A, and FIG. 9 (b) shows the luminance at the point B. FIG.

First, the compensation value is stored in the memory 450 (S602). The compensation value may be calculated using various information calculated when the sensing for the external compensation is actually performed in the manufacturing process of the panel or may be calculated through various simulations and then stored in the memory 450 .

The compensation value may be the same for all the subpixels 110 formed in the panel 100 or may be changed according to the gray of the input image data or may be changed according to the position of the horizontal line in the panel Or may be changed according to the color corresponding to the input image data or may be changed according to at least one of the gray of the input image data, the position of the horizontal line, and the hue.

For example, the compensation value may be the same for all the sub-pixels 110 formed in the panel 100. [ That is, the compensation value may be the same for all colors and all subpixels.

The compensation value may be changed according to the color of the input image data. FIG. 10 shows the compensation value (? V) for each of red (R), white (W), green (G) and blue (B), and the compensation value differs for each color. For example, the compensation value for the R input image data corresponding to the R subpixel is 0.01 V, the compensation value for the W input image data corresponding to the W subpixel is 0.013 V, the G input image data corresponding to the G subpixel The compensation value for the B input image data corresponding to the B subpixel can be 0.009V.

Also, the compensation value may be changed according to the gray of the input image data. For example, as shown in FIG. 10, the compensation value for the input image data may be variously changed according to gray.

Also, the compensation value may be changed according to the position of the horizontal line on which the subpixel to which the input image data is to be output is formed. For example, in FIG. 10A, L represents the compensation value of each gray of the R input image data output to the subpixel formed on the horizontal line formed in the upper end X of the panel 100 , M represents a compensation value of each gray of R input image data output to a subpixel formed in a horizontal line formed in a middle portion (Y) of the panel, and N is a value formed at the lower end portion (Z) of the panel The compensation value of each gray of the R input image data output to the subpixel formed in the horizontal line.

Also, the compensation value may be calculated in consideration of at least one of gray of the input image data, position of the horizontal line, and hue. That is, as described above, since the compensation value can be variously changed according to the gray of the input image data, the position of the horizontal line, and the color, the compensation value can be calculated in consideration of all the information have.

Meanwhile, FIG. 11 shows current flowing into the organic light emitting diode in the sub-pixel in which no sensing is performed and current flowing into the organic light emitting diode in the sub-pixel in which the sensing is performed. Referring to FIG. 11, when sensing is performed, since the current flowing into the organic light emitting diode is small, when the subpixel is driven with the same data voltage (Vdata), the luminance is lowered. Therefore, in the present invention, in order to increase the luminance by supplementing the current, the compensation value is added to the input image data as described above. The compensation value added to the input image data may be a value related to gray. However, by virtue of the compensation value, the compensation data voltage rises. Therefore, in the above description, for convenience of explanation, it has been described that the compensation value is a voltage.

Next, in the sensing mode, a data voltage is sequentially supplied to the subpixels forming one unit pixel 120, and a characteristic change of the driving transistors formed in each of the pixels is sensed. That is, for each horizontal line, sensing for external compensation is performed (S604).

In this case, one sensing line is formed in the unit pixel 120 as shown in FIG. That is, while the reference voltage is applied to one sensing line, a data voltage is supplied only to one of the pixels forming the unit pixel, Can be detected.

By performing the above process four times, sensing data for four subpixels forming one unit pixel can be generated. Accordingly, the sensing data for all the subpixels formed in one horizontal line can be generated.

The calculation unit 410 may calculate the external compensation value using the sensing data. As described above, the specific method for calculating the external compensation value can be applied to the methods described in the open patent documents and various patent documents filed by the present applicant.

The sensing mode is executed at a blank time between a frame and a frame, as shown in Fig. In the blank time, a data voltage is not output to the data lines. However, since the data voltages already charged in the respective subpixels formed in the respective horizontal lines HL are continuously maintained, as shown in FIG. 8, the image is output through the panel even at the blank time .

However, since the sensing data voltage for the sensing is supplied to the horizontal line in which the sensing is performed, for example, the subpixels formed in the nth horizontal line nHL in FIG. 8, In the subpixels formed on the n horizontal line (nHL), no image is output during the blank time.

A period from the timing at which the compensated data voltage is output to the data line until the sensing is performed until the image is output by the compensated data voltage after the sensing is performed corresponds to one frame period.

In other words, the period from when one of the general data voltages is output to the horizontal line on which no sensing is performed, until the image is output by another normal data voltage is referred to as one frame period. In this case, a period from the timing at which the compensation data voltage is output before the sensing is performed until the image is output by the compensation data voltage after the sensing is performed corresponds to one frame period. When the one frame period has elapsed, the general data voltage or the external compensation data voltage is supplied to the subpixels formed on the horizontal line on which the sensing is performed.

Next, when the input image data corresponding to the horizontal line on which the sensing is performed is received in the display mode, the data sorting unit compensates the input image data using the compensation value stored in the memory 450 Into image data. The data driver 300, particularly, the data voltage output unit 310 converts the compensated image data into the compensated data voltage and outputs the compensated data voltage to the data line.

For example, as shown in Fig. 8, for the nHL horizontal line, when the sensing is performed in the blank time, i.e., the sensing mode, a period before and after the blank time is set to the display mode .

Accordingly, the data sorting unit 430 generates the compensated image data corresponding to the subpixels formed in the nth horizontal line nHL in the frame immediately before the blank time comes, And the data voltage output unit 310 converts the compensated image data into the compensated data voltage and outputs the compensated data voltage to the data line.

The data sorting unit 430 generates the compensation video data corresponding to the subpixels formed in the nth horizontal line nHL at the end of the blank time, And the data voltage output unit 310 converts the compensated image data into the compensated data voltage and outputs the compensated data voltage to the data line.

The luminance CD corresponding to the compensated image data is larger than the luminance RD corresponding to the input image data, as shown in Figs. 8 and 9B.

For example, even if the data voltages corresponding to the input image data are not output to the subpixels formed in the nth horizontal line nHL during the blank time, the input image data The data voltage of the compensated image data, which outputs a luminance greater than the luminance corresponding to the data voltage by the nth horizontal line nHL, is output to the subpixels formed in the nth horizontal line nHL. Therefore, the average value of the luminance of the nth horizontal line nHL, to which the data voltages corresponding to the compensated image data are outputted, is similar to the luminance of the horizontal line outputting the data voltages corresponding to the input image data .

Therefore, as shown in FIG. 9, a difference in brightness is not generated between the subpixel A formed on the horizontal line where the sensing is not performed and the subpixel B formed on the horizontal line on which the sensing is performed Do not. Accordingly, a phenomenon that the horizontal line on which the sensing is performed is displayed darker than the horizontal line on which the sensing is not performed can be prevented.

Finally, in the display mode, when the input image data corresponding to the horizontal line on which the sensing is not performed is received, if the external compensation for the input image data is requested, And converts the image data into the external compensation image data using the external compensation value. Thus, the external compensation data voltage is output.

The data sorting unit 430 rearranges the input image data according to the structure of the panel to convert the input image data into the general image data if no external compensation is required for the input image data in the display mode. That is, the input image data for which external compensation is not required is converted into the general image data, and the data voltage output unit 310 converts the general image data into the general data voltage and outputs the general data voltage to the data line.

To be more specific, the external compensation data voltage, the compensation data voltage and the general data voltage are output to the data line in the display mode.

In particular, the compensated data voltage is output as subpixels formed on the horizontal line on which the sensing is performed, and the external compensated data voltage and the common data voltage are subpixels formed on the horizontal line .

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: panel 200: gate driver
300: Data driver 400: Timing controller
110: subpixel 120: unit pixel
410: Calculator 420: Control signal generator
430: Data sorting unit 440: Output unit
450: Memory

Claims (8)

Wherein the subpixels are formed and the sensing for external compensation is performed for each horizontal line;
A sensing unit for performing sensing for external compensation for each horizontal line of the panel to collect sensing data;
A calculating unit for determining a characteristic change of each subpixel using the sensing data and calculating an external compensation value;
A data arrangement unit for converting the input image data into compensated image data using a compensation value when the input image data corresponding to the horizontal line on which the sensing is performed is received; And
Wherein the compensation data voltage corresponding to the compensated image data is output to the data line formed on the panel before and after the sensing is performed and when the sensing is performed, And outputting the data driver. The method according to claim 1,
The data lines are formed in the first direction of the panel, the sensing lines are formed in parallel with the data lines, and each of the sensing lines constitutes each unit pixel formed in one horizontal line Wherein the display device is connected to at least three sub-pixels. The method according to claim 1,
The sensing unit includes:
And performs the sensing at a blank time that is formed between the frame and the frame and no video signal is output. The method according to claim 1,
Wherein the data sorting unit comprises:
And when the input image data corresponding to the horizontal line on which the sensing is performed is received, the compensation value is added to the input image data and converted into the compensated image data. 5. The method of claim 4,
Wherein the luminance corresponding to the compensated image data is larger than the luminance corresponding to the input image data. The method according to claim 1,
Wherein the compensation value
Or the gray level of the input image data, or is changed according to the position of the horizontal line in the panel, or the input image data Is changed according to at least one of gray of the input image data, position of the horizontal line, and the hue. The method according to claim 1,
A period from the timing at which the compensation data voltage is output before the sensing is performed until the image is output by the compensation data voltage after the sensing is performed corresponds to one frame period Device. The method according to claim 1,
Wherein the data alignment unit performs external compensation of the input image data using the external compensation value according to a calculation unit control signal transmitted from the calculation unit when the input image data corresponding to a horizontal line on which no sensing is performed is received, And converts the input image data into general image data by rearranging the input image data without external compensation,
Wherein the data driver outputs the external compensation video data or the general video data to a data line formed on the panel in each horizontal period.

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